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123-720: Similar to the AK-47 's symbolism with Third World and leftist revolutionaries, the TEC-9 is notorious in American pop culture for its association with criminal gangs , drive-by shootings and mass shootings in the 1990s, with it most notably being used during the 101 California Street shooting and the Columbine High School massacre . Interdynamic AB, a Swedish firearms manufacturer based in Stockholm , designed

246-478: A screw thread . More screw threads are produced each year than any other machine element . There are many methods of generating threads, including subtractive methods (many kinds of thread cutting and grinding, as detailed below); deformative or transformative methods (rolling and forming; molding and casting); additive methods (such as 3D printing ); or combinations thereof. There are various methods for generating screw threads. The method for any one application

369-405: A better thread quality than tapping as it offers better chip evacuation. Tapping uses a tool the same size as the thread, forcing the chip through the thread for evacuation. Thread cutting, as compared to thread forming and rolling, is used when full thread depth is required, when the quantity is small, when the blank is not very accurate, when threading up to a shoulder is required, when threading

492-401: A blank by pressing a shaped tool, commonly called a 'thread rolling die' against the blank, in a process similar to knurling . These processes are used for large production runs because typical production rates are around one piece per second. Forming and rolling produce no swarf and less material is required because the blank size starts smaller than a blank required for cutting threads; there

615-411: A change in blank diameter will affect the major diameter by an approximate ratio of 3 to 1. Production rates are usually three to five times faster than thread cutting. (planetary roller) In casting and molding the threads are directly formed by the geometry of the mold cavity in the mold or die . When the material freezes in the mold, it retains the shape after the mold is removed. The material

738-411: A common vehicle's metal body and into an opponent attempting to use these things as cover. The 7.62×39mm M43 projectile does not generally fragment when striking an opponent and has an unusual tendency to remain intact even after making contact with bone. The 7.62×39mm round produces significant wounding in cases where the bullet tumbles (yaws) in tissue, but produces relatively minor wounds in cases where

861-441: A contour-like simulation of helical interpolation. The tooling used for thread milling can be solid or indexable. For internal threads, solid cutters are generally limited to holes larger than 6 mm (0.24 in), and indexable internal thread cutting tools are limited to holes larger than 12 mm (0.47 in). The advantage is that when the insert wears out it is easily and more cost effectively replaced. The disadvantage

984-515: A curved 30-round magazine. Kalashnikov's rifles, the AK-1 (with a milled receiver ) and AK-2 (with a stamped receiver) proved to be reliable weapons and were accepted to a second round of competition along with other designs. These prototypes (also known as the AK-46) had a rotary bolt, a two-part receiver with separate trigger unit housing, dual controls (separate safety and fire selector switches), and

1107-410: A cutting tap due to the chip build-up in the hole. Note that the tap drill size differs from that used for a cutting tap and that an accurate hole size is required because a slightly undersized hole can break the tap. Proper lubrication is essential because of the frictional forces involved, therefore a lubricating oil is used instead of cutting oil . When considering the blank diameter tolerance,

1230-431: A cutting tap without the flutes. There are lobes periodically spaced around the tap that actually do the thread forming as the tap is advanced into a properly sized hole. Since the tap does not produce chips, there is no need to periodically back out the tap to clear away chips, which, in a cutting tap, can jam and break the tap. Thus thread forming is particularly suited to tapping blind holes, which are tougher to tap with

1353-683: A delay between the initial recoil impulse of the piston and the bolt unlocking sequence, allowing gas pressures to drop to a safe level before the seal between the chamber and the bolt is broken. The AK-47 does not have a gas valve; excess gases are ventilated through a series of radial ports in the gas cylinder. Unlike many other rifle platforms, such as the AR-15 platform, the Kalashnikov platform bolt locking lugs are chamfered allowing for primary extraction upon bolt rotation which aids reliable feeding and extraction, albeit not with that much force due to

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1476-415: A dust cover and prevents the charging handle from being pulled fully to the rear when it is on safe. It is operated by the shooter's right fore-fingers and has three settings: safe (up), full-auto (center), and semi-auto (down). The reason for this is that a soldier under stress will push the selector lever down with considerable force, bypassing the full-auto stage and setting the rifle to semi-auto. To set

1599-465: A hassle since the end of the rivet has to be ground off and a new one set after the part is replaced." For the further developed AK models, see Kalashnikov rifles . Manufacturing countries of AK-47 and its variants in alphabetical order. A private company Kalashnikov Concern (formerly Izhmash) from Russia has repeatedly claimed that the majority of foreign manufacturers are producing AK-type rifles without proper licensing . The AK-47's accuracy

1722-465: A hole all in one compact cycle. The advantage is this process eliminates a tool, tool-holder , and tool change. The disadvantage is that the process is limited to hole depth no greater than three times the diameter of the tool. A method of helical broaching was developed in the 2010s that shortens the toolpath of tapping. To a casual observer (without slow motion ), it looks rather similar to traditional tapping but with faster movement into and out of

1845-410: A left- or right-hand thread can be created with the same tool. Additionally, for large, awkward workpieces (such as a fire hydrant casting), it is simply easier to let the workpiece sit stationary on a table while all needed machining operations are performed on it with rotating tools, as opposed to rigging it up for rotation around the axis of each set of threads (that is, for the "arms" and "mouth" of

1968-586: A lighter stamped steel version and the most ubiquitous variant of the entire AK series of firearms. In the 1960s, the Soviets introduced the RPK light machine gun, an AK-type weapon with a stronger receiver, a longer heavy barrel, and a bipod, that eventually replaced the RPD light machine gun. Mikhail Kalashnikov began his career as a weapon designer in 1941 while recuperating from a shoulder wound that he received during

2091-824: A lightweight magazine with an aluminum body with a prominent reinforcing waffle rib pattern weighing 0.19 kg (0.42 lb) empty was developed for the AKM that proved to be too fragile, and the small issued amount of these magazines were quickly withdrawn from service. As a replacement steel-reinforced 30-round plastic 7.62×39mm box magazines were introduced. These rust-colored magazines weigh 0.24 kg (0.53 lb) empty and are often mistakenly identified as being made of Bakelite (a phenolic resin ), but were fabricated from two parts of AG-S4 molding compound (a glass-reinforced phenol- formaldehyde binder impregnated composite), assembled using an epoxy resin adhesive. Noted for their durability, these magazines did however compromise

2214-612: A means to improve the street value of the weapon. AK-47 The AK-47 , officially known as the Avtomat Kalashnikova (Russian: Автомат Калашникова , lit. 'Kalashnikov's automatic [rifle]'; also known as the Kalashnikov or just AK ), is an assault rifle that is chambered for the 7.62×39mm cartridge. Developed in the Soviet Union by Russian small-arms designer Mikhail Kalashnikov , it

2337-410: A muzzle velocity of 715 m/s (2,350 ft/s). The cartridge weight is 16.3 g (0.6 oz), and the projectile weight is 7.9 g (122 gr). The original Soviet M43 bullets are 123-grain boat-tail bullets with a copper-plated steel jacket, a large steel core, and some lead between the core and the jacket. The AK has excellent penetration when shooting through heavy foliage, walls, or

2460-623: A newer design, the AK-74 , which uses 5.45×39mm ammunition. This new rifle and cartridge had only started to be manufactured in Eastern European nations when the Soviet Union collapsed , drastically slowing the production of the AK-74 and other weapons of the former Soviet bloc. The AK-47 was designed to be a simple, reliable fully automatic rifle that could be manufactured quickly and cheaply, using mass production methods that were state of

2583-511: A newer model. The following year Intratec introduced the AB-10 ("AB" standing for " A fter B an"), a TEC-9 Mini without a threaded muzzle/barrel shroud and sold with a smaller 10-round magazine instead of 20- or 32-round magazines. However, the AB-10 still accepted the larger capacity magazines of the pre-ban TEC-9 models which were often acquired by users in place of the standard magazine. In 1999,

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2706-517: A non-reciprocating charging handle located on the left side of the weapon. This design had many similarities to the StG 44. In late 1946, as the rifles were being tested, one of Kalashnikov's assistants, Aleksandr Zaitsev, suggested a major redesign to improve reliability. At first, Kalashnikov was reluctant, given that their rifle had already fared better than its competitors. Eventually, however, Zaitsev managed to persuade Kalashnikov. In November 1947,

2829-422: A notched rear tangent iron sight calibrated in 100 m (109 yd) increments from 100 to 800 m (109 to 875 yd). The front sight is a post adjustable for elevation in the field. Horizontal adjustment requires a special drift tool and is done by the armory before the issue or if the need arises by an armorer after the issue. The sight line elements are approximately 48.5  mm (1.9  in ) over

2952-468: A redesigned version designated the AKM (M for "modernized" or "upgraded"; in Russian: Автомат Калашникова Модернизированный [ Avtomat Kalashnikova Modernizirovanniy ]) was introduced in 1959. This new model used a stamped sheet metal receiver and featured a slanted muzzle brake on the end of the barrel to compensate for muzzle rise under recoil. In addition, a hammer retarder was added to prevent

3075-455: A result, the AK-47 has a service/system life of approximately 6,000, to 10,000, to 15,000 rounds. The AK-47 was designed to be a cheap, simple, easy-to-manufacture rifle, perfectly matching Soviet military doctrine that treats equipment and weapons as disposable items. As units are often deployed without adequate logistical support and dependent on "battlefield cannibalization" for resupply, it

3198-470: A significant weight reduction and allows a soldier to carry more ammunition for the same weight. All 7.62×39mm AK magazines are backward compatible with older AK variants. 10.12 kg (22.3 lb) is the maximum amount of ammo that the average soldier can comfortably carry. It also allows for the best comparison of the three most common 7.62×39mm AK magazines. Most Yugoslavian and some East German AK magazines were made with cartridge followers that hold

3321-629: A single steel billet makes them highly resistant to damage. These magazines are so strong that "Soldiers have been known to use their mags as hammers, and even bottle openers". This contributes to the AK-47 magazine being more reliable but makes it heavier than U.S. and NATO magazines. The early slab-sided steel AK-47 30-round detachable box magazines had 1 mm (0.039 in) sheet-metal bodies and weighed 0.43 kg (0.95 lb) empty. The later steel AKM 30-round magazines had lighter sheet-metal bodies with prominent reinforcing ribs weighing 0.33 kg (0.73 lb) empty. To further reduce weight,

3444-405: A single- or multiple-form cutter. In one variant of form-milling, the single-form cutter is tilted to the helix angle of the thread and then fed radially into the blank. The blank is then slowly rotated as the cutter is precisely moved along the axis of the blank, which cuts the thread into the blank. This can be done in one pass, if the cutter is fed to the full thread depth, or in two passes, with

3567-420: A slanted angle with the bore axis. The muzzle is threaded for the installation of various muzzle devices such as a muzzle brake or a blank-firing adaptor . The gas block of the AK-47 features a cleaning rod capture or sling loop. Gas relief ports that alleviate gas pressure are placed horizontally in a row on the gas cylinder. The fire selector is a large lever located on the right side of the rifle; it acts as

3690-500: A submachine gun design in 1942 and a light machine gun design in 1943. Early in 1944, Kalashnikov was given some 7.62×39mm M43 cartridges and informed that other designers were working on weapons for this new Soviet small-arms cartridge. It was suggested that a new weapon might well lead to greater things. He then undertook work on the new rifle. In 1944, he entered a design competition with this new 7.62×39mm, semi-automatic, gas-operated, long-stroke piston carbine, strongly influenced by

3813-423: A tapered thread, or when the material is brittle. A common method of threading is cutting with taps and dies. Unlike drill bits , hand taps do not automatically remove the chips they create. A hand tap cannot cut its threads in a single rotation because it creates long chips which quickly jam the tap (an effect known as "crowding" ), possibly breaking it. Therefore, in manual thread cutting, normal wrench usage

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3936-472: A wide range of conditions and possessed convenient handling characteristics. In 1949, it was adopted by the Soviet Army as the "7.62 mm Kalashnikov rifle (AK)". There were many difficulties during the initial phase of production. The first production models had stamped sheet metal receivers with a milled trunnion and butt stock insert and a stamped body. Difficulties were encountered in welding

4059-411: Is 30 rounds. There are also 10-, 20-, and 40-round box magazines, as well as 75-round drum magazines. The AK-47's standard 30-round magazines have a pronounced curve that allows them to smoothly feed ammunition into the chamber. Their heavy steel construction combined with "feed-lips" (the surfaces at the top of the magazine that control the angle at which the cartridge enters the chamber) machined from

4182-451: Is actually plastic molding that is the principal method (by sheer volume) of thread generation in manufacturing today. Of course, this fact highlights the importance of the moldmakers getting the mold just right (in preparation for millions of cycles, usually at high speed). Cast threads in metal parts may be finished by machining, or may be left in the as-cast state. (The same can be said of cast gear teeth.) Whether or not to bother with

4305-545: Is best described as a hybrid of previous rifle technology innovations. "Kalashnikov decided to design an automatic rifle combining the best features of the American M1 Garand and the German StG 44 ." Kalashnikov's team had access to these weapons and did not need to "reinvent the wheel". Kalashnikov himself observed: "A lot of Russian Army soldiers ask me how one can become a constructor, and how new weaponry

4428-451: Is calibrated at 50 m (55 yd), for improved night fighting. The AK-47 was originally equipped with a buttstock, handguard, and an upper heat guard made from solid wood. With the introduction of the Type 3 receiver the buttstock, lower handguard, and upper heat guard were manufactured from birch plywood laminates . Such engineered woods are stronger and resist warping better than

4551-541: Is chosen based on constraints—time, money, degree of precision needed (or not needed), what equipment is already available, what equipment purchases could be justified based on resulting unit price of the threaded part (which depends on how many parts are planned), etc. In general, certain thread-generating processes tend to fall along certain portions of the spectrum from toolroom -made parts to mass-produced parts, although there can be considerable overlap. For example, thread lapping following thread grinding would fall only on

4674-459: Is circular interpolation in one plane [typically XY] with simultaneous linear interpolation along a third axis [typically Z]; the CNC control model must be one that supports using the third axis) or a simulation of it using extremely small increments of 3-axes linear interpolation (which is not practical to program manually but can be programmed easily with CAD/CAM software). The cutter geometry reflects

4797-446: Is commonly employed on turret lathes and screw machines . The second type takes the form of a self-opening die head . This type is more common than the former, but is limited by not being able to form the last 1.5 to 2 threads against shoulders. Planetary dies are used to mass-produce threads up to 1 in (25 mm) in diameter. Thread forming is performed using a fluteless tap , or roll tap , which closely resembles

4920-468: Is designed. These are very difficult questions. Each designer seems to have his own paths, his own successes and failures. But one thing is clear: before attempting to create something new, it is vital to have a good appreciation of everything that already exists in this field. I myself have had many experiences confirming this to be so." Some claimed that Kalashnikov copied designs like Bulkin's TKB-415 or Simonov's AVS-31 . Kalashnikov started work on

5043-416: Is done on a grinding machine using specially dressed grinding wheels matching the shape of the threads. The process is usually used to produce accurate threads or threads in hard materials; a common application is ball screw mechanisms. There are three types: center-type grinding with axial feed , center-type infeed thread grinding and centerless thread grinding . Center-type grinding with an axial feed

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5166-403: Is faster than using a single-form cutter but it is limited to threads with a helix angle less than 3°. It is also limited to blanks of a substantial diameter and no longer than 2 in (51 mm). Another variant of form-milling involves holding the cutter's axis orthogonally (no canting to the thread's helix angle) and feeding the cutter in a toolpath that will generate the thread. The part

5289-577: Is generally sufficient to hit an adult male torso out to about 300 m (328 yd), though even experts firing from prone or bench rest positions at this range were observed to have difficulty placing ten consecutive rounds on target. Later designs did not significantly improve the rifle's accuracy. An AK can fire a 10-shot group of 5.9 in (15 cm) at 100 m (109 yd), and 17.5 in (44 cm) at 300 m (328 yd) The newer stamped-steel receiver AKM models, while more rugged and less prone to metal fatigue, are less accurate than

5412-531: Is heated to a liquid, or mixed with a liquid that will either dry or cure (such as plaster or cement). Alternatively, the material may be forced into a mold as a powder and compressed into a solid, as with graphite . Although the first thoughts that come to mind for most machinists regarding threading are of thread cutting processes (such as tapping, single-pointing, or helical milling), Smid points out that, when plastic bottles for food, beverages, personal care products, and other consumer products are considered, it

5535-409: Is longer than the length of the desired thread. First, the grinding wheel is fed into the blank to the full thread depth. Then the blank is slowly rotated through approximately 1.5 turns while axially advancing through one pitch per revolution. Finally, the centerless thread grinding process is used to make head-less set screws in a similar method as centerless grinding . The blanks are hopper-fed to

5658-443: Is more cost-effective to replace rather than repair weapons. The AK-47 has small parts and springs that need to be replaced every few thousand rounds. However, "Every time it is disassembled beyond the field stripping stage, it will take some time for some parts to regain their fit, and some parts may tend to shake loose and fall out when firing the weapon. Some parts of the AK-47 line are riveted together. Repairing these can be quite

5781-540: Is on soda (pop) bottles. A common example of die-cast threads is on cable glands (connectors/fittings). Many, perhaps most, threaded parts have potential to be generated via additive manufacturing ( 3D printing ), of which there are many variants, including fused deposition modeling , selective laser sintering , direct metal laser sintering , selective laser melting , electron beam melting , layered object manufacturing , and stereolithography . For most additive technologies, it has not been long since they emerged from

5904-453: Is required, rarely employed except for the leadscrews or ballscrews of high-end machine tools. Internal threads can be electrical discharge machined (EDM) into hard materials using a sinker style machine. Thread forming and thread rolling are processes for forming , rather than cutting, screw threads, with the former referring to creating internal threads and the latter external threads. In both of these processes threads are formed into

6027-536: Is similar to the second generation, but is darker colored and has a matte non-reflective surface finish. The current issue is a steel-reinforced matte true black non- reflective surface finished 7.62×39mm 30-round magazine, fabricated from ABS plastic weighing 0.25 kg (0.55 lb) empty. Early steel AK-47 magazines are 9.75 in (248 mm) long; the later ribbed steel AKM and newer plastic 7.62×39mm magazines are about 1 in (25 mm) shorter. The transition from steel to mainly plastic magazines yields

6150-424: Is the cycle time is generally longer than solid tools. Note that solid multiple-form thread cutting tools look similar to taps, but they differ in that the cutting tool does not have a backtaper and there is not a lead-in chamfer. This lack of a lead-in chamfer allows the threads to be formed within one pitch length of the bottom of a blind hole. Thrilling is the process of thr eading and dr illing (accomplished in

6273-405: Is the most common of the three. It is similar to cutting a thread on a lathe with a single-point cutting tool , except the cutting tool is replaced with a grinding wheel. Usually a single ribbed wheel is used, although multiple ribbed wheels are also available. To complete the thread multiple passes are commonly required. Center-type infeed thread grinding use a grinding wheel with multiple ribs that

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6396-424: Is the originating firearm of the Kalashnikov (or "AK") family of rifles . After more than seven decades since its creation, the AK-47 model and its variants remain one of the most popular and widely used firearms in the world. Design work on the AK-47 began in 1945. It was presented for official military trials in 1947, and, in 1948, the fixed- stock version was introduced into active service for selected units of

6519-436: Is to cut the threads 1/2 to 2/3 of a turn (180 to 240 degree rotation), then reverse the tap for about 1/6 of a turn (60 degrees) until the chips are broken by the back edges of the cutters. It may be necessary to periodically remove the tap from the hole to clear the chips, especially when a blind hole is threaded. For continuous tapping operations (i.e., power tapping) specialized spiral point or "gun" taps are used to eject

6642-413: Is typically a 15 to 20% material savings in the blank, by weight. A rolled thread can be easily recognized on fasteners that were formed from an unstopped blank because the thread has a larger diameter than the blank rod from which it has been made; however, necks and undercuts can be cut or rolled onto blanks with threads that are not rolled, and some fasteners are made from blanks with a reduced shank in

6765-425: Is usually a stationary workpiece, such as a boss on a valve body (in external thread milling) or a hole in a plate or block (in internal thread milling). This type of thread milling uses essentially the same concept as contouring with an endmill or ball-nose mill, but the cutter and toolpath are arranged specifically to define the "contour" of a thread. The toolpath is achieved either using helical interpolation (which

6888-559: The Battle of Bryansk . Kalashnikov himself stated..."I was in the hospital, and a soldier in the bed beside me asked: 'Why do our soldiers have only one rifle for two or three of our men when the Germans have automatics?' So I designed one. I was a soldier, and I created a machine gun for a soldier. It was called an Avtomat Kalashnikova, the automatic weapon of Kalashnikov—AK—and it carried the year of its first manufacture, 1947." The AK-47

7011-615: The Interdynamic MP-9 , intended as an inexpensive 9mm submachine gun based on the Carl Gustav M/45 for military applications. The firearm was initially intended for adoption by the South African apartheid government, though it was rejected and shipped to various other nations. Ultimately, Interdynamic did not find a government buyer. As a result, the weapon was taken by lead designer George Kellgren to

7134-653: The PPSh-41 submachine guns and outdated Mosin–Nagant bolt-action rifles that armed most of the Soviet Army. The Soviets soon developed the 7.62×39mm M43 cartridge , used in the semi-automatic SKS carbine and the RPD light machine gun . Shortly after World War II, the Soviets developed the AK-47 rifle, which quickly replaced the SKS in Soviet service. Introduced in 1959, the AKM is

7257-498: The PSO-1 Optical Sniper Sight . The side rails allow for the removal and remounting of optical accessories without interfering with the zeroing of the optic. However, the 100 series side folding stocks cannot be folded with the optics mounted. The AK-47 and its variants have been and are made in dozens of countries, with "quality ranging from finely engineered weapons to pieces of questionable workmanship." As

7380-770: The Soviet Army . In early 1949, the AK was officially accepted by the Soviet Armed Forces and used by the majority of the member states of the Warsaw Pact . The model and its variants owe their global popularity to their reliability under harsh conditions, low production cost (compared to contemporary weapons), availability in virtually every geographic region, and ease of use. The AK has been manufactured in many countries and has seen service with armed forces as well as irregular forces and insurgencies throughout

7503-542: The dental implant and bone screw fields, where selective laser sintering and selective laser melting have produced threaded titanium implants. Often subtractive, additive, deformative, or transformative methods are combined in whatever ways are advantageous. Such multidisciplinary manufacturing falls under classifications including rapid prototyping , desktop manufacturing , direct manufacturing , direct digital manufacturing , digital fabrication , instant manufacturing , or on-demand manufacturing . Inspection of

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7626-578: The 1990s the TEC-9 also developed a reputation for its use by American street gangs and organized crime syndicates, who were attracted to the large capacity 32-round magazines and low cost of the firearm. The TEC-9 was produced from 1985 until 1994, when the model and TEC-DC9 variants were banned nationally in the United States, among the 19 firearms banned by name in the now-expired 1994 Federal Assault Weapons Ban (AWB). This ban forced Intratec to cease their manufacture, and forced them to introduce

7749-526: The AK-47 to full-auto requires the deliberate action of centering the selector lever. To operate the fire selector lever, right-handed shooters have to briefly remove their right hand from the pistol grip, which is ergonomically sub-optimal. Some AK-type rifles also have a more traditional selector lever on the left side of the receiver, just above the pistol grip. This lever is operated by the shooter's right thumb and has three settings: safe (forward), full-auto (center), and semi-auto (backward). The AK-47 uses

7872-554: The American M1 Garand. The new rifle was in the same class as the SKS-45 carbine, with a fixed magazine and gas tube above the barrel. However, the new Kalashnikov design lost out to a Simonov design. In 1946, a new design competition was initiated to develop a new rifle. Kalashnikov submitted a gas-operated rifle with a short-stroke gas piston above the barrel, a breechblock mechanism similar to his 1944 carbine, and

7995-463: The Kalashnikov assault rifle abroad were of the AKM variant, partially due to the much easier production of the stamped receiver. This model is the most commonly encountered, having been produced in much greater quantities. All rifles based on the Kalashnikov design are often colloquially referred to as "AK-47s" in the West and some parts of Asia, although this is only correct when applied to rifles based on

8118-461: The M43 round. This change also reduces penetration in ballistic gelatin to ~25 in (64 cm) for the newer M67 round versus ~29 in (74 cm) for the older M43 round. However, the wounding potential of M67 is mostly limited to the small permanent wound channel the bullet itself makes, especially when the bullet yaws. To fire, the operator inserts a loaded magazine, pulls back and releases

8241-627: The NATO E-type Silhouette Target (a human upper body half and head silhouette) of the AK-47 and the later developed AK-74, M16A1, and M16A2 rifles were measured by the US military under ideal proving ground conditions in the 1980s as follows: Under worst field exercise circumstances, the hit probabilities for all the tested rifles were drastically reduced, from 34% at 50m down to 3–4% at 600m with no significant differences between weapons at each range. The following table represents

8364-473: The Russian circular error probable method for determining accuracy, which involves drawing two circles on the target, one for the maximum vertical dispersion of hits and one for the maximum horizontal dispersion of hits. They then disregard the hits on the outer part of the target and only count half of the hits (50% or R 50 ) on the inner part of the circles. This significantly reduces the overall diameter of

8487-615: The TEC-DC9 Mini was notoriously used by Dylan Klebold , one of the perpetrators of the Columbine High School massacre, ending with him using it to take his own life. In 1994, the TEC-9 was used by murder suspect Bennie Lee Lawson in a shooting at Henry Daly Building in Washington D.C. , killing two FBI agents, one police officer and wounding another FBI agent and a civilian before taking his own life. The TEC-9

8610-561: The United States domestic market as an open-bolt semi-automatic pistol, redesigned to eliminate its collapsible stock and vertical foregrip features per the National Firearms Act of 1934 and marketed under the subsidiary Interdynamic USA brand. Still, the design was deemed too easy to convert to an automatic weapon . Due to this, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) forced Interdynamic USA to redesign

8733-429: The additional expense of a machining operation depends on the application. For parts where the extra precision and surface finish is not strictly necessary, the machining is forgone in order to achieve a lower cost. With sand casting parts this means a rather rough finish; but with molded plastic or die-cast metal, the threads can be very nice indeed straight from the mold or die. A common example of molded plastic threads

8856-460: The art in the Soviet Union during the late 1940s. The AK-47 uses a long-stroke gas system generally associated with high reliability in adverse conditions. The large gas piston, generous clearance between moving parts, and tapered cartridge case design allow the gun to endure large amounts of foreign matter and fouling without failing to cycle. The AK fires the 7.62×39mm cartridge with

8979-586: The bayonet lug under the front sight base. All current model AKM rifles can mount under-barrel 40 mm grenade launchers such as the GP-25 and its variants, which can fire up to 20 rounds per minute and have an effective range of up to 400 meters. The main grenade is the VOG-25 (VOG-25M) fragmentation grenade which has a 6 m (9 m) (20 ft (30 ft)) lethality radius. The VOG-25P/VOG-25PM ("jumping") variant explodes 0.5–1 metre (1.6–3.3 ft) above

9102-416: The bolt open when empty; however, most AK magazine followers allow the bolt to close when the magazine is empty. Accessories supplied with the rifle include a 387 mm (15.2 in) long 6H3 bayonet featuring a 200 mm (7.9 in) long spear point blade. The AK-47 bayonet is installed by slipping the 17.7 mm (0.70 in) diameter muzzle ring around the muzzle and latching the handle down on

9225-529: The bore axis. The " point-blank range " battle zero setting " П " standing for постоянная (constant) on the 7.62×39mm AK-47 rear tangent sight element corresponds to a 300 m (328 yd) zero. These settings mirror the Mosin–Nagant and SKS rifles, which the AK-47 replaced. For the AK-47 combined with service cartridges, the 300 m battle zero setting limits the apparent "bullet rise" within approximately −5 to +31 cm (−2.0 to 12.2 in) relative to

9348-455: The bullet exits before beginning to yaw. In the absence of yaw, the M43 round can pencil through tissue with relatively little injury. Most, if not all, of the 7.62×39mm ammunition found today is of the upgraded M67 variety. This variety deleted the steel insert, shifting the center of gravity rearward, and allowing the projectile to destabilize (or yaw) at about 3.3 in (8.4 cm), nearly 6.7 in (17 cm) earlier in tissue than

9471-456: The charging handle, and then pulls the trigger . In semi-automatic, the firearm fires only once, requiring the trigger to be released and depressed again for the next shot. In fully automatic, the rifle continues to fire automatically cycling fresh rounds into the chamber until the magazine is exhausted or pressure is released from the trigger. After ignition of the cartridge primer and propellant, rapidly expanding propellant gases are diverted into

9594-471: The chips and prevent crowding. Single-point threading , also colloquially called single-pointing (or just thread cutting when the context is implicit), is an operation that uses a single-point tool to produce a thread form on a cylinder or cone. The tool moves linearly while the precise rotation of the workpiece determines the lead of the thread. The process can be done to create external or internal threads (male or female). In external thread cutting,

9717-413: The configuration of the dies : flat dies , two-die cylindrical , three-die cylindrical , and planetary dies . The flat die system has two flat dies. The bottom one is held stationary and the other slides. The blank is placed on one end of the stationary die and then the moving die slides over the blank, which causes the blank to roll between the two dies forming the threads. Before the moving die reaches

9840-593: The conventional one-piece patterns, do not require lengthy maturing, and are cheaper. The wooden furniture was finished with the Russian amber shellac finishing process. AKS and AKMS models featured a downward-folding metal butt-stock similar to that of the German MP40 submachine-gun , for use in the restricted space in the BMP infantry combat vehicle , as well as by paratroops. All 100 series AKs use plastic furniture with side-folding stocks. The standard magazine capacity

9963-430: The end of its stroke the blank rolls off the stationary die in a finished form. The two-die cylindrical process is used to produce threads up to 6 in (150 mm) in diameter and 20 in (510 mm) in length. There are two types of three-die processes; the first has the three dies move radially out from the center to let the blank enter the dies and then closes and rotates to roll the threads. This type of process

10086-577: The extreme toolroom end of the spectrum, while thread rolling is a large and diverse area of practice that is used for everything from microlathe leadscrews (somewhat pricey and very precise) to the cheapest deck screws (very affordable and with precision to spare). Threads of metal fasteners are usually created on a thread rolling machine. They may also be cut with a lathe , tap or die . Rolled threads are stronger than cut threads, with increases of 10% to 20% in tensile strength and possibly more in fatigue resistance and wear resistance. Thread milling has

10209-467: The federal level since 2004, the TEC-9 and similar variants are banned, often by name, in several US states including California, New York , New Jersey , and Maryland . Quantities of an illegally-made 9mm machine pistol were seized in Europe in 2017. Despite being improvised weapons (and not developed by Intratec) they were nonetheless marked as "Intratec TEC-9", believed to possibly have been done as

10332-546: The finished screw threads can be achieved in various ways, with the expense of the method tailored to the requirements of the product application. Shop-floor inspection of a thread is often as simple as running a nut onto it (for male threads) or a bolt into it (for female threads). This is plenty good enough for many applications (e.g., MRO or hobbyist work), although it is not good enough for most commercial manufacturing. Higher-precision methods are discussed below. Commercial-grade inspection of screw threads can involve most of

10455-485: The firearm into a closed-bolt system, which was harder to convert to an automatic weapon. This variant was called the KG-99, and was popularized when it made frequent appearances on the popular television show Miami Vice , where it was legally converted to full auto by Title II manufacturers . The KG-9 and KG-99 have an open-end upper receiver tube where the bolt , recoil springs, and buffer plate are held in place by

10578-408: The first not being to the full thread depth. This process is mainly used on threads larger than 1.5 in (38 mm). It is commonly used to cut large- lead or multiple-lead threads. A similar variant using a multiple-form cutter exists, in which the process completes the thread in one revolution around the blank. The cutter must be longer than the desired thread length. Using a multiple-form cutter

10701-480: The forged/milled receivers of their predecessors: the milled AK-47s are capable of shooting 3 to 5 in (8 to 13 cm) groups at 100 yd (91 m), whereas the stamped AKMs are capable of shooting 4 to 6 in (10 to 15 cm) groups at 100 yd (91 m). The best shooters can hit a man-sized target at 800 m (875 yd) within five shots (firing from a prone or bench rest position) or ten shots (standing). The single-shot hit-probability on

10824-486: The gas cylinder above the barrel through a vent near the muzzle. The build-up of gases inside the gas cylinder drives the long-stroke piston and bolt carrier rearward and a cam guide machined into the underside of the bolt carrier, along with an ejector spur on the bolt carrier rail guide, rotates the bolt approximately 35° and unlocks it from the barrel extension via a camming pin on the bolt. The moving assembly has about 5.5 mm (0.2 in) of free travel, which creates

10947-467: The grain with the thread profile. Also, materials with good deformation characteristics are necessary for rolling; these materials include softer (more ductile) metals and exclude brittle materials, such as cast iron . Tolerances are typically ±0.001 in. (±0.025 mm), but tolerances as tight as ±0.0006 in (±0.015 mm) are achievable. Surface finishes range from 6 to 32 micro-inches. There are four main types of thread rolling, named after

11070-409: The grinding wheels, where the thread is fully formed. Common centerless thread grinding production rates are 60 to 70 pieces per minute for a 0.5 in (13 mm) long set screw. Rarely, thread cutting or grinding (usually the latter) will be followed by thread lapping in order to achieve the highest precision and surface finish achievable. This is a toolroom practice when the highest precision

11193-438: The ground. The AK-47 can also mount a (rarely used) cup-type grenade launcher , the Kalashnikov grenade launcher that fires standard RGD-5 Soviet hand grenades. The maximum effective range is approximately 150 meters. This launcher can also be used to launch tear gas and riot control grenades. All current AKs (100 series) and some older models have side rails for mounting a variety of scopes and sighting devices, such as

11316-418: The groups. They then use both the vertical and horizontal measurements of the reduced groups to measure accuracy. When the R 50 results are doubled, the hit probability increases to 93.7%. The vertical and horizontal mean (R 50 ) deviations with service ammunition at 800 m (875 yd) for AK platforms are. Threading (manufacturing) In manufacturing , threading is the process of creating

11439-415: The guide and ejector rails, causing high rejection rates. Instead of halting production, a heavy machined receiver was substituted for the sheet metal receiver. Even though production of these milled rifles started in 1951, they were officially referred to as AK-49, based on the date their development started, but they are widely known in the collectors' and current commercial market as "Type 2 AK-47". This

11562-404: The hole. It uses a specific tool geometry and toolpath to position rapidly, broach the thread in a single half-turn, and then retract rapidly, shortening the cycle time and consuming less energy. It reduces the cost of threading for any holes that can safely allow the two small fast-helix grooves that it leaves behind along with the thread, which could be true in many applications. Thread grinding

11685-422: The hydrant). There are various types of thread milling, including several variants of form-milling and a combination of drilling and threading with one cutter, called thrilling . One main advantage against tapping, is that tapping only starts making a complete thread profile on the third thread, whereas thread milling will produce a complete thread profile from the top to the bottom. Form-milling uses either

11808-519: The invention of the screw-cutting lathe , which was the origin of single-point threading as we know it today. Today engine lathes and CNC lathes are the commonly used machines for single-point threading. On CNC machines, the process is quick and easy (relative to manual control) due to the machine's ability to constantly track the relationship of the tool position and spindle position (called "spindle synchronization"). CNC software includes "canned cycles", that is, preprogrammed subroutines, that obviate

11931-499: The laboratory end of their historical development, but further commercialization is picking up speed. To date, most additive methods tend to produce a rough surface finish and tend to be restricted in the material properties that they can produce, and thus their earliest commercial victories have been in parts for which those restrictions were acceptable. However, the capabilities are continually growing. Good examples of threaded parts produced with additive manufacturing are found in

12054-467: The later TEC-DC9 is that rings to hold the sling were moved from the side of the gun with the cocking handle to a removable stamped metal clip in the back of the gun. In 1993, the weapon was the subject of further controversy following its use in the 101 California Street shootings That same year, California amended the 1989 Roberti–Roos Assault Weapons Control Act (AWCA) , effective January 2000, to ban handguns having features such as barrel shrouds . During

12177-413: The line of sight. Soldiers are instructed to fire at any target within this range by simply placing the sights on the center of mass (the belt buckle, according to Russian and former Soviet doctrine) of the enemy target. Any errors in range estimation are tactically irrelevant, as a well-aimed shot will hit the torso of the enemy soldier. Some AK-type rifles have a front sight with a flip-up luminous dot that

12300-410: The lower receiver, solving the problem of lower receiver failure when using hot ammo. Following the 1989 Cleveland School massacre , the TEC-9 was placed on California 's list of banned weapons. To circumvent this, Intratec rebranded a variant of the TEC-9 as TEC-DC9 from 1990 to 1994 (with DC standing for " D esigned for C alifornia"). The most noticeable external difference between the TEC-9 and

12423-432: The manual programming of a single-point threading cycle. Parameters are entered (e.g., thread size, tool offset, length of thread), and the machine does the rest. All threading could feasibly be done using a single-point tool, but because of the high speed and thus low unit cost of other methods (e.g., tapping, die threading, and thread rolling and forming), single-point threading is usually only used when other factors of

12546-405: The manufacturing process happen to favor it (e.g., if only a few threads need to be made, if an unusual or unique thread is required, or if there is a need for very high concentricity with other part features machined during the same setup. ) Threads may be milled with a rotating milling cutter if the correct helical toolpath can be arranged. This was formerly arranged mechanically, and it

12669-590: The measurement and then perform the table lookup (as opposed to recalculating each time). The 3-wire method is also used when high precision is needed to inspect a specific diameter, commonly the pitch diameter, or on specialty threads such as multi-start or when the thread angle is not 60°. Ball-shaped micrometer anvils can be used in similar fashion (same trigonometric relationship, less cumbersome to use). Digital calipers and micrometers can send each measurement (data point) as it occurs to storage or software through an interface (such as USB or RS-232 ), in which case

12792-479: The new prototypes (AK-47s) were completed. The rifle used a long-stroke gas piston above the barrel. The upper and lower receivers were combined into a single receiver. The selector and safety were combined into a single control lever/dust cover on the right side of the rifle and the bolt handle was attached to the bolt carrier. This simplified the design and production of the rifle. The first army trial series began in early 1948. The new rifle proved to be reliable under

12915-431: The original three receiver types. In most former Eastern Bloc countries, the weapon is known simply as the "Kalashnikov" or "AK". The differences between the milled and stamped receivers includes the use of rivets rather than welds on the stamped receiver, as well as the placement of a small dimple above the magazine well for stabilization of the magazine. In 1974, the Soviets began replacing their AK-47 and AKM rifles with

13038-433: The piece can either be held in a chuck or mounted between two centers . With internal thread cutting, the piece is held in a chuck. The tool moves across the piece linearly, taking chips off the workpiece with each pass. Usually 5 to 7 light cuts create the correct depth of the thread. The coordination of various machine elements including leadscrew , slide rest, and change gears was the technological advance that allowed

13161-429: The plastic/polymer lower receiver frame. This design only allows for 115 grains (7.5 g) 9mm ammunition, and if a heavier grain ammunition or hot loads are used, the plastic lower receiver will fail or crack, rendering the firearm unusable. Later versions of the TEC-9 and AB-10 had a threaded upper receiver tube at the rear and a screw-on end cap to contain the bolt, recoil spring, and buffer plate even if removed from

13284-505: The region to be rolled to maintain a constant major diameter from thread to unthreaded shank. Unless faced off, the end threads of a rolled fastener have a cupped end, as the surplus material in the tapering down final threads collapses uniformly over the end of the blank. Materials are limited to ductile materials because the threads are cold formed . However, this increases the thread's yield strength, surface finish, hardness , wear resistance , and fatigue strength due to conformance of

13407-424: The reverse order) internal threads using a specialized cutting tool on a CNC mill. The cutting tool tip is shaped like a drill or center-cutting endmill, while the body has a thread-shaped form with a countersink cutter form near the shank. The cutter first plunges to drill the hole. Then the thread is circularly interpolated just like the multiple-form cutter described above. This tool drills, chamfers , and threads

13530-459: The rifle's camouflage and lacked the small horizontal reinforcing ribs running down both sides of the magazine body near the front that were added on all later plastic magazine generations. A second-generation steel-reinforced dark-brown (color shades vary from maroon to plum to near black ) 30-round 7.62×39mm magazine was introduced in the early 1980s, fabricated from ABS plastic. The third generation steel-reinforced 30-round 7.62×39mm magazine

13653-410: The same inspection methods and tools used to inspect other manufactured products, such as micrometers ; vernier or dial calipers ; surface plates and height gauges ; gauge blocks ; optical comparators ; white light scanners ; and coordinate-measuring machines (CMMs). Even industrial radiography (including industrial CT scanning ) can be used, for example, to inspect internal thread geometry in

13776-412: The short distance the bolt carrier travels before acting on the locking lug. The Kalashnikov platform then uses an extractor claw along with a fin shaped ejector to eject the spent cartridge case. The rifle received a barrel with a chrome-lined bore and four right-hand grooves at a 240 mm (1 in 9.45 in) or 31.5 calibers rifling twist rate . The gas block contains a gas channel that is installed at

13899-421: The table lookup is done in an automated way, and quality assurance and quality control can be achieved using statistical process control . Each method of thread generation has its own detailed history. Therefore, a comprehensive discussion is beyond the scope of this article; but much historical information is available in related articles, including: The first patent for the cold rolling of screw threads

14022-428: The thread pitch but not its lead; the lead (thread helix angle) is determined by the toolpath. Tapered threads can be cut either with a tapered multiple-form cutter that completes the thread in one revolution using helical interpolation, or with a straight or tapered cutter (of single- or multiple-form) whose toolpath is one or more revolutions but cannot use helical interpolation and must use CAD/CAM software to generate

14145-402: The valleys of the thread and then measuring from wire to wire with standard (flat) anvils. A conversion factor (produced by a straightforward trigonometric calculation) is then multiplied with the measured value to infer a measurement of the thread's pitch diameter . Tables of these conversion factors were established many decades ago for all standard thread sizes, so today a user need only take

14268-504: The way that an optical comparator can inspect external thread geometry. Conical micrometer anvils, specifically suited to resting on the sides of the thread, are made for various thread angles , with 60° being the most common. Mics with such anvils are usually called "thread mics" or "pitch mics" (because they directly measure the pitch diameter). Users who lack thread mics rely instead on the "3-wire method", which involves placing 3 short pieces of wire (or gauge pins ) of known diameter into

14391-426: The weapon from firing out of battery (without the bolt being fully closed), during rapid or fully automatic fire. This is also sometimes referred to as a "cyclic rate reducer", or simply "rate reducer", as it also has the effect of reducing the number of rounds fired per minute during fully automatic fire. The rifle was also roughly one-third lighter than the previous model. Most licensed and unlicensed productions of

14514-502: The world. As of 2004 , "of the estimated 500 million firearms worldwide, approximately 100 million belong to the Kalashnikov family, three-quarters of which are AK-47s". The model is the basis for the development of many other types of individual, crew-served, and specialized firearms. During World War II , the Sturmgewehr 44 rifle used by German forces made a deep impression on their Soviet counterparts. The select-fire rifle

14637-458: Was a more costly process, but the use of machined receivers accelerated production as tooling and labor for the earlier Mosin–Nagant rifle's machined receiver were easily adapted. Partly because of these problems, the Soviets were not able to distribute large numbers of the new rifles to soldiers until 1956. During this time, production of the interim SKS rifle continued. Once the manufacturing difficulties of non-milled receivers had been overcome,

14760-586: Was also used in the 1990 drive-by shooting at Nashville, Tennessee West End Synagogue by Grand Wizard of the Ku Klux Klan Leonard William Armstrong . In 2001, the Supreme Court of California ruled that Intratec was not liable for the 1993 101 California Street attacks, and that same year Intratec was dissolved and production of the AB-10 model ceased. Although still found on the used firearms market and legal on

14883-605: Was chambered for a new intermediate cartridge , the 7.92×33mm Kurz , and combined the firepower of a submachine gun with the range and accuracy of a rifle. On 15 July 1943, an earlier model of the Sturmgewehr was demonstrated before the People's Commissariat of Arms of the USSR . The Soviets were impressed with the weapon and immediately set about developing an intermediate caliber fully automatic rifle of their own, to replace

15006-554: Was issued in 1836 to William Keane of Monroe, N.Y. However, the dies for rolling the threads onto the screw blanks were made of cast iron, which is brittle, so the machine was not successful. The process languished until 1867, when Harvey J. Harwood of Utica, New York filed a patent for the cold-rolling of threads on wood screws. Further efforts to cold-roll threads on screws followed, but none seemed to meet with much success until Hayward Augustus Harvey (1824–1893) of Orange, N.J. filed his patents of 1880 and 1881. Charles D. Rogers of

15129-465: Was suitable for mass-production work although uncommon in job-shop work. With the widespread dissemination of affordable, fast, precise CNC , it became much more common, and today internal and external threads are often milled even on work where they would formerly have been cut with taps, die heads, or single-pointing. Some advantages of thread milling, as compared to single-point cutting or taps and dies, are faster cycle times, less tool breakage, and that

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